Four centuries ago, on October 12, 29209, the Clans took Omni-2
It was a time of cruel and merciless rebellion, long before the creation of the Council of Truth. It's only 7 years before this event that a few loose coalitions of workers in the North of Rubi-Ka secretly began to call themselves "Clans".
So the Clans occupied Omni-2 and drove out, imprisoned, or executed

all Omni-Tek personnel. They renamed the city Athen after the name of one of the Clans leaders who died in the attack.
(And, yes, there is a distorsion between the look of Athen and the fact the battle raged four centuries ago, hence the reason why Znore decided than the Clans rebuilit a part of the city.)